Not having read the'sing to the stars story', it's all speculation. It could be that the main character is a child. Children are often full of wonder and imagination. This child might believe that the stars are listening to their songs. And there could be a magical creature in the story, like a star - fairy or something, who is attracted by the child's singing and becomes part of the story.
It's possible that there is a special animal character in the story. Maybe a little bird that also loves the stars and joins the child in singing to them. The bird could be a guide for the child, showing the best places to look at the stars and how to sing in a way that the stars seem to respond.
I don't know the 'in the stars story' well enough to say who the main characters are. It could be a young girl who has a special connection to the stars.
The 'sing to the stars story' could be a very imaginative and magical one. It might tell of a world where the stars are living entities. The protagonist, perhaps a lonely singer, discovers that the stars can hear their songs. As they sing, the stars respond in some way, like shining brighter or sending down a soft glow. It could also be a story about how music has the power to bridge the gap between the earthly world and the celestial realm of the stars.
Some of the main characters include Anzu, who plays an important role in the idol world of the story. Then there's Trickstar's members like Hokuto Hidaka, Subaru Akehoshi, etc. They are key players in the story's idol - related events.
Without further information about the 'stars at noon story', it's impossible to determine the main characters. However, it could be a story about a young child who is the only one able to see the stars at noon and has to convince the adults around them that it's real. Or perhaps it's a story about a group of villagers who experience a strange omen in the form of stars at noon and have to figure out what it means together.
The main characters in the Alchemy Stars story are quite diverse. There's a young and brave protagonist who is on a quest to uncover the truth about the world and the powers within it. There are also some mentor - like characters who guide the protagonist along the way. Each character has their own personality traits, like some being more impulsive while others are more cautious. Their interactions shape the story as they face challenges, make decisions, and strive to protect their world from the encroaching darkness.
The main characters are likely the Sailor Guardians like Sailor Moon, Sailor Mercury, Sailor Mars, etc.
In the 'the moon and the stars story', the moon is a central character. It could be a wise, old moon that has seen many things. The stars are also main characters, perhaps some are brave little stars, while others are shy. They all interact with the moon in different ways, like the moon might be a protector of the stars, or the stars might be the moon's little helpers in some grand celestial plan.
Since we don't have much information, it's difficult to say for sure. But it could be the lost stars themselves.
Since I don't know the exact 'lost in the stars story', I can't say for sure. But it could be an astronaut, a stargazer, or some sort of space traveler.